Patent GB-937750-A (GB)
Title: Metal loading of molecular sieves
IPC: B01J23/70
Filed: 1959-09-23
Abstract: A zeolitic molecular sieve is loaded with Fe, Ni, Co, Cu, Ag, Au, Cd, Zn, Hg, T, Sn, Pb, by contacting the zeolite with a water soluble salt of one of the above metals, dehydrating the ion-exchanged sieve and thereafter contacting with a reducing agent, such as hydrogen, carbon monoxide, alkali metal vapour or hydrazine to reduce the metal cation to elemental metal.  Such deposited metal may thereafter be contacted with oxygen to oxidize the metal.  Suitable zeolites are the natural chabazite, faujasite, erionite, mordenite, gmelinite and calcium analcite and the synthetic zeolitic molecular sieves designated A, D, L, R, S, T, X and Y prepared according to Specifications 777,232, 777,233, 868,846, 880,702, 909,264, 909,265, 909,266 and 912,936, respectively.  Dehydration of the ion exchanged sieve is effected at about 350 DEG C. in an inert gas stream or in a vacuum and reduction is effected at a temperature below 350 DEG C. According to Examples (I) zeolite X was contacted with nickel nitrate solution washed, dried at 100 DEG C. and heated in hydrogen at 300 DEG -350 DEG C.  The temperature was then raised to 500 DEG C. and the zeolite thereafter cooled in a hydrogen atmosphere.  The zeolite contained 8,6% of nickel.  Examples II-VI illustrate the production of silver, mercury, cadmium, lead and copper-containing sieves respectively by similar methods.  (VIII) Zeolite A was slurried with silver nitrate solution and the sieve after washing was dried at 100 DEG C. and dehydrated at 350 DEG -400 DEG C.  Hydrogen was thereafter passed over the sieve at up to 200 DEG C. and a product containing about 23% of silver resulted.  X-ray diffraction analysis indicated that hydrogen exchange had occurred.  (IX) Mordenite was ground and contacted with silver nitrate solution, dried and reduced at 350 DEG C. in hydrogen to yield a silver containing sieve the basic structure of which was a hydrogen-exchanged form of mordenite. (X) Sodium zeolitex was contacted with an aqueous solution of thallous sulphate and was then dehydrated at 375 DEG C. under reduced pressure.  The resulting zeolite was mixed with metallic sodium and heated to 150 DEG -180 DEG C. under argon.  The product contained 31% of thallium. The reducing agents are oxidized to cations which take up positions in the sieve structure formally occupied by the cation which was reduced.  (XI) Zeolite X in divalent copper form was dehydrated at 375 DEG C. in nitrogen and then reduced to 350 DEG C. with carbon monoxide.  Replacement of the reduced copper cations was apparently effected with hydrogen ions obtained from residual water.  (XII) Zeolite X in divalent copper form was dried and suspended in water under an inert atmosphere.  Hydrazine hydrochloride was added followed by a dropwise addition of sodium hydroxide.  Nitrogen was evolved and excess hydrazine was decomposed by heating to 100 DEG C. The resulting zeolite contained 8% by weight of copper.  The zeolites obtained may be employed as catalysts, as selective getters and as a means for the controlled addition of metals to reaction systems. Specifications 937,748 and 937,749 also are referred to.